One is the wily veteran with years of experience on his side.
The other stands out for his youth and promise.
Together, they will carry Canada's colours into a key Davis Cup doubles match Saturday with Spain.
Daniel Nestor, a 40-year-old with world-class credentials, and Vasek Pospisil, 22, a young star still trying to make his way in international tennis, will face Marcel Granollers and Marc Lopez. It's a tall order for the Canadians as their Spanish rivals are rated among the best on the globe right now, based on their 2012 ATP World Tour doubles title.
Granollers and Lopez also reached the semifinals of this year's Australian Open but have struggled in Davis Cup play.
"I think it'll be a tough match, for sure," Nestor said after a long training session earlier this week. "They're one of the top teams.
"We're playing pretty well, too. We've played a lot together."
Nestor and Pospisil teamed up in the 2012 London Olympics on the fabled Wimbledon grass. They have also played at other times in Davis Cup events, posting a win in Israel 2011 that helped Canada return to the World Group.
A win Saturday would be their most significant Davis Cup accomplishment.
Spain has sent a makeshift squad to this first-round tie. Four of its highest-ranked players — David Ferrer (fourth), Rafael Nadal (fifth), Nicolas Almagro (11th) and Fernando Verdasco (24th) — have stayed home rather than travel to the best-of-five series at the University of British Columbia.
While Nadal and Almagro are out with injuries, Ferrer and Verdasco chose to rest.
Hence, a win in doubles, which often turns out to be the pivotal event in a Davis Cup tie, could go a long way towards Canada's victory hopes.
Canada has never advanced beyond the first round of World Group play, which is open to the top-16 teams. Spain, a five-time Davis Cup champion, was upset by the Czech Republic in the 2012 final.
But, because of the notable absentees, Spain will be hard pressed to live up to its current No. 1 ranking.
"We have a great chance, obviously," said Nestor. "They're not sending their best team. They have a good doubles team but their singles players aren't their best.
"We have to take advantage of that. This is the best opportunity that we've had to win a World Group (tie.) So, basically, we have to seize the moment."
Nestor, who has won 80 career doubles titles — including the 2000 Olympic gold medal — brings court savvy and experience while Pospisil provides a big serve and creativity.
"I like playing with him because I feel like he's a natural doubles player," said Nestor. "He's got the game and he's got the movement and all that. So I feel like we move well together."
But Pospisil's mobility could be limited by a health issue. He is battling back from a bout of mononucleosis and felt he would be come too fatigued if he competed in singles. As a result, captain Martin Laurendeau has replaced him in singles with Frank Dancevic of Niagara Falls, Ont.
Fatigue will also come into question with Nestor, who is the oldest player competing this weekend. But he had little difficulty during a long workout Wednesday.
Nestor, who emerged on the Davis Cup scene as a 19-year-old in Vancouver against Sweden two decades ago, takes great pride in his longevity. He also feels he has been more fortunate than many of his peers when it comes to staying fit.
"One of the reasons why I continue to play is because I feel more healthy than I did, say, six or seven years ago when I was having problems with my arm or whatever," Nestor said.
With his wife expecting the couple's second child in another month, Nestor is starting to question how much longer he'll play. But it appears unlikely he will call it quits in the near future.
"My wife's been supportive of me," said Nestor. "She understands and she wants me to play, and I'm obviously doing well for now."
Like in a marriage, personalities also play a prominent role in on-court partnerships, according to Pospisil.
During practice, Nestor was exuberant while Pospisil played the role of student learning from the master.
However in matches, Nestor is usually a picture of calmness while Pospisil's face can get flushed when he is angry with himself.
"I bring a lot of energy and I try to fire him up," said Pospisil. "I think, maybe, he needs some of that.
"And then I need, maybe, somebody to calm me down sometimes — because I can get pretty intense."
Nestor said he is more emotional than he used to be, and can still dwell too much on the negative. But Pospisil can be "a little bit too emotional."
Nestor said Pospisil can be very competitive and expects a lot from himself.
"So if he's not playing well all the time I think he's getting upset," said Nestor. "(I) just try to use my experience to calm him down at times."